This invention relates to a disposable wearing article adapted to absorption and to containment of bodily discharges.
Conventional disposable wearing articles comprise a liquid-pervious topsheet facing a wearer's body, a liquid-impervious backsheet facing away from the wearer's body, a liquid-absorbent panel interposed between these top- and backsheet, a pair of end flaps extending outside longitudinally opposite ends of the panel and a pair of side flaps extending outside transversely opposite side edges of the panel and are composed of a front waist region, a rear waist region and a crotch region extending between these waist regions.
The conventional wearing article as has been described above will be described more in details in reference to FIGS. 8–10 of the accompanying drawings. FIG. 8 is a partially cutaway developed plan view showing the article 1C as its front and rear waist regions 23, 25 disconnected from each other. FIGS. 9 and 10 are sectional views taken along lines E—E and F—F, respectively, in FIG. 8, showing the article 1C being slightly curved. In FIG. 8, a waist-circumferential direction is indicated by an arrow X and a longitudinal direction is indicated by an arrow Y. This article 1C is so-called pull-on disposable diaper and actually placed on the market in the trade name of REHABILI-PANTS (supplied from Uni-Charm Corporation).
The article 1C comprises a liquid-pervious topsheet 20, a substantially liquid-impervious backsheet 21 and a liquid-absorbent panel 22 interposed between these top- and backsheets 20, 21. The article 1C has front and rear waist regions 23, 25, a crotch region 24 extending between the waist regions 23, 25, a pair of end flaps 26 and a pair of side flaps 27. While it is not shown, the side flaps 27 of the front and rear waist regions 23, 25 are overlaid and joined together by means of a plurality of welding lines 28 arranged intermittently in the longitudinal direction.
The topsheet 20 is made of a hydrophilic fibrous nonwoven fabric f6 and slightly larger than an upper surface of the panel 22, entirely covering the upper surface of the panel 22. The topsheet 20 has its inner surface intermittently joined to the upper surface of the panel 22 by means of an adhesive g.
The backsheet 21 comprises a breathable but liquid-impervious plastic film f7, a breathable but hydrophobic first fibrous nonwoven fabric layer f8 under the film f7 and a breathable but hydrophobic second fibrous nonwoven fabric layer f9 underlying the first fibrous nonwoven fabric layer f8. The film f7 is larger than the panel 22 and covers an entire under surface of the panel 22. The first and second fibrous nonwoven fabric layers f8, f9 are respectively larger than the film f7 and cover an entire under surface of the panel 22. Portions of these first and second fibrous nonwoven fabric layers f8, f9 extending outward beyond longitudinally opposite ends and transversely opposite side edges of the panel 22 define the end flaps 26 and the side flaps 27. The panel 22 is a mixture of fluff pulp and super-absorbent polymer particles or a mixture of fluff pulp, super-absorbent polymer particles and thermoplastic synthetic resin fibers, in any case, compressed to a desired thickness.
In a zone where the panel 22 is present, the film f7 has its inner surface intermittently joined to the lower surface of the panel 22 by means of the adhesive g and its outer surface intermittently joined to an inner surface of the first fibrous nonwoven fabric layer f8 by means of the adhesive g. The first and second fibrous nonwoven fabric layers f8, f9 are not joined in the zone where the panel 22 is present but intermittently joined in the end flaps 26 and the side flaps 27 by means of the adhesive g. The topsheet 20 and the first fibrous nonwoven fabric layer f8 are intermittently joined in the end flaps 26 and the side flaps 27 by means of the adhesive g. A hot melt adhesive is used as the adhesive g for the article 1C.
The breathable but liquid-impervious film f7 joined to the under surface of the panel 22 prevents any amount of body discharges such as urine, moisture contained in feces or menstrual discharge having been absorbed by the panel 22 from permeating the first and second fibrous nonwoven fabric layers f8, f9 and, in addition, prevents the panel 22 from getting out of its initial shape in the article 1C.
Based on a series of measurement conducted on this article 1C, it has been found that a vapor permeability of 2113 g/m2·24 hrs is obtained when the film f7 is coated with 5 g/m2 of the adhesive g in the zone where the panel 22 is present and a vapor permeability of 1983 g/m2·24 hrs is obtained when the film f7 is coated with 10 g/m2 of the adhesive g. Measurement of the vapor permeability is subjected to the article 1C without the topsheet in the thickness direction of the article 1C in the zone where the panel 22 is present.
While this article 1C may probably prevent any significant amount of body discharges from permeating the first and second fibrous nonwoven fabric layers f8, f9, the adhesive g by means of which the film f7 is joined to the panel 22 and the first fibrous nonwoven fabric layer f8 deteriorates the vapor permeability of the film f7 and the permeability of the article 1C in the zone where the panel 22 is present. With the article 1C put on a wearer's body, it is difficult to let out vapor from the interior to the exterior of the article 1C and thereby to protect the wearer from uncomfortable stuffiness possibly generated within the article 1C.